Search results for "Global warming"

Increased water temperature decreases predation rate of an important sea star predator on sea urchins.

2011

Ecological impacts of global warming and water abstraction on lakes and reservoirs due to changes in water level and related changes in salinity

2015

According to the Intergovernmental Panel on Climate Change report released in September 2014, unprecedented changes in temperature and precipitation patterns have been recorded globally in recent decades and further change is predicted to occur in the near future, mainly as the result of human activity. In particular, projections show that the Mediterranean climate zone will be markedly affected with significant implications for lake water levels and salinity. This may be exacerbated by increased demands for irrigation water. Based on long-term data from seven lakes and reservoirs covering a geographical gradient of 52 of latitudes and a literature review, we discuss how changes in water le…

Posidonia oceanica living in enclosed coastal lagoon as model for testing the effect of climate change on organism near their limit of thermal tolera…

2009

Climate change and population genetic structure of marine species

2011

Climate change influences populations by reducing or extirpating local populations, by disrupting patterns of migration and by shifting geographical distributions. These events can affect genetic population structure in several ways. Molecular markers have been used in numerous population genetic and phylogeographical studies of marine species and have detected population responses to climate change in the last few decades, such as range expansions, adaptative shifts and declines or increases in abundance. Little is known, however, about the molecular and physiological basis of adaptive responses to climate change in marine Mediterranean species. The Mediterranean Sea ecosystem is a ‘living…

Climate change potentially affect keystone predation in subtidal system.

2014

Larval Development of Arbacia lixula (Linneo, 1758) in two Marine Protected Area: preliminary data.

2010

The sea urchin Arbacia lixula is a crucial species in driving the algal assemblages dynamic of the infralittoral zone. A. lixula is considered a thermophilic species and its increase in abundance in western Mediterranean waters, probably is due to an increase in seawater temperature. The aim of this study was to examine the reproductive success of A. lixula by larval development. The study was conducted within two Sicilian MPA (Capo Gallo-Isola delle Femmine and Ustica), characterized by photophilic algae, the same exposure and seawater temperature. In each area, twenty random specimens was sampled from May to September 2010, and mature gametes were collected from six males and six females …

Greenhouse Gas Emissions from Membrane Bioreactors

2017

Nowadays, it is widely accepted that wastewater treatment plants (WWTPs) are significant sources of greenhouse gas (GHG) emission, contributing to the anthropogenic sources. Among the GHG emitted from WWTPs, nitrous oxide (N2O) has been identified of having the major interest/concern, since its high global warming potential (GWP), is 298 times higher than that of CO2 and also to its capability to react with stratospheric ozone causing the layer depletion. Up to now, most of the experimental investigations have been carried out on conventional activated sludge (CAS) processes. The knowledge of N2O emission from advanced technologies such membrane bioreactors (MBRs) is still very limited. The…

Greenhouse gases from membrane bioreactors: a pilot plant case study

2015

In this study the N2O emitted from the aerobic and anoxic tank of a Sequential Batch (SB) Membrane Bioreactor (MBR) pilot plant has been investigated. The SB-MBR pilot plant was fed with a mixture of synthetic and real wastewater. The influence of salinity on N2O concentration was analyzed by gradually increasing the salinity by addition of salt to concentrations ranging from 0 to 10 gNaCl L-1. The results demonstrated that the N2O concentration of the gaseous samples was strongly influenced by the salinity in the range of 0.25 ppm to 3.4 ppm salinity. This result was explained by lower autotrophic kinetics due to the biomass lysis. Dissolved oxygen concentration and salinity were found to …

Quantifying sensitivity and uncertainty analysis of a new mathematical model for the evaluation of greenhouse gas emissions from membrane bioreactors

2015

Abstract A new mathematical model able to quantify greenhouse gas (GHG) emissions in terms of carbon dioxide (CO 2 ) and nitrous oxide (N 2 O) for a Membrane Bioreactor (MBR) is presented. The proposed mathematical model is of the Activated Sludge Model (ASM) family and takes into account simultaneously both biological and physical processes (e.g., membrane fouling). An analysis of the key factors and sources of uncertainty influencing GHG emissions is also presented. Specifically, the standardized regression coefficient, the Extended-FAST and a Monte Carlo based method are employed for assessing model factors which influence three performance indicators: effluent quality index, operational…

Towards a conceptual mathematical tool linking physical and biological processes for a reduction of ghg emissions from an mb-mbr plant

2016

The current study explores the influence of the air flow rate on greenhouse gas (GHG) emissions (direct and indirect), the operational costs (OCs), the effluent quality index (EQI) and effluent fines (EF). An University Cape Town (UCT) moving bed (MB) membrane bioreactor (MBR) pilot plant has been considered as case study where the influence of the air flow rate on the biological and physical processes has been analyzed. Constitutive relationships between the air flow rate and some performance indicators (i.e., EQI, OCs, direct and indirect GHG emissions) have been identified. Results showed that the EQI increases at low flow rate likely due to the dissolved oxygen (DO) limitation in the bi…